Semiconductor device and method of fabricating the same

ABSTRACT

Disclosed are semiconductor devices and methods of fabricating the same. The method comprises sequentially stacking a lower sacrificial layer and an upper sacrificial layer on a substrate, patterning the upper sacrificial layer to form a first upper sacrificial pattern and a second upper sacrificial pattern, forming a first upper spacer and a second upper spacer on sidewalls of the first upper sacrificial pattern and a second upper sacrificial pattern, respectively, using the first and second upper spacers as an etching mask to pattern the lower sacrificial layer to form a plurality of lower sacrificial patterns, forming a plurality of lower spacers on sidewalls of the lower sacrificial patterns, and using the lower spacers as an etching mask to pattern the substrate. The first and second upper spacers are connected to each other.

CROSS-REFERENCE TO RELATED APPLICATION

This U.S. nonprovisional application claims priority under 35 U.S.C §119 to Korean Patent Application No. 10-2018-0133668, filed on Nov. 2,2018, in the Korean Intellectual Property Office, the entire contents ofwhich are hereby incorporated by reference.

BACKGROUND

The present inventive concepts relate to a semiconductor device and amethod of fabricating the same, and more particularly, to asemiconductor device and a method of fabricating the same with reducedfabrication cost and time.

Semiconductor devices have been increasingly required for highintegration with the advanced development of electronic industry. Forexample, semiconductor devices have been increasingly requested for highreliability, high speed, and/or multi-functionality. Semiconductordevices have gradually become more complicated and integrated to meetthese requested characteristics.

SUMMARY

Some example embodiments of the present inventive concepts provide asemiconductor device and a method of fabricating the same with reducedfabrication cost and time.

According to example embodiments, the disclosure is directed to a methodof fabricating a semiconductor device, the method comprising:sequentially stacking a lower sacrificial layer and an upper sacrificiallayer on a substrate; patterning the upper sacrificial layer to form afirst upper sacrificial pattern and a second upper sacrificial pattern;forming a first upper spacer and a second upper spacer on sidewalls ofthe first upper sacrificial pattern and the second upper sacrificialpattern, respectively; patterning the lower sacrificial layer, using thefirst and second upper spacers as an etching mask, to form a pluralityof lower sacrificial patterns; forming a plurality of lower spacers onsidewalls of the lower sacrificial patterns; and patterning thesubstrate using the plurality of lower spacers as an etching mask,wherein the first and second upper spacers are connected to each other.

According to example embodiments, the disclosure is directed to a methodof fabricating a semiconductor device, the method comprising: forming afirst upper sacrificial pattern and a second upper sacrificial patternrespectively on a first region and a second region of a substrate; andperforming a quadruple patterning technology (QPT) process in which thefirst and second upper sacrificial patterns are used as mandrels to forma plurality of active patterns on an upper portion of the substrate,wherein the active patterns are not formed on a third region between thefirst region and the second region.

According to example embodiments, the disclosure is directed to asemiconductor device, comprising: a substrate; first to third activepatterns sequentially provided along a first direction on an upperportion of the substrate, wherein the first to third active patternsextend lengthwise in parallel along a second direction; a pair of firstinner inactive patterns spaced apart in the second direction from eachother across the second and third active patterns; and a pair of firstouter inactive patterns spaced apart in the second direction from eachother across the first to third active patterns and the pair of firstinner inactive patterns.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a plan view showing a semiconductor device accordingto some example embodiments of the present inventive concepts.

FIG. 1B illustrates a cross-sectional view taken along line A-A′ of FIG.1A.

FIG. 1C illustrates a cross-sectional view taken along line B-B′ of FIG.1A.

FIG. 1D illustrates a cross-sectional view taken along line C-C′ of FIG.1A.

FIGS. 2A, 3A, 4A, 5A, 6A, 7A, and 8A illustrate plan views showing amethod of fabricating a semiconductor device depicted in FIGS. 1A, 1B,1C, and 1D.

FIGS. 2B, 3B, 4B, 5B, 6B, 7B, and 8B illustrate cross-sectional viewstaken along line A-A′ of FIGS. 2A, 3A, 4A, 5A, 6A, 7A, and 8A,respectively.

FIG. 9A illustrates a plan view showing a semiconductor device accordingto some example embodiments of the present inventive concepts.

FIG. 9B illustrates a cross-sectional view taken along line A-A′ of FIG.9A.

FIG. 9C illustrates a cross-sectional view taken along line B-B′ of FIG.9A.

FIGS. 10A, 11A, 12A, 13A, 14A, 15A, and 16A illustrate plan viewsshowing a method of fabricating a semiconductor device depicted in FIGS.9A, 9B, and 9C.

FIGS. 10B, 11B, 12B, 13B, 14B, 15B, and 16B illustrate cross-sectionalviews taken along line A-A′ of FIGS. 10A, 11A, 12A, 13A, 14A, 15A, and16A, respectively.

DETAILED DESCRIPTION OF EMBODIMENTS

FIG. 1A illustrates a plan view showing a semiconductor device accordingto some example embodiments of the present inventive concepts. FIG. 1Billustrates a cross-sectional view taken along line A-A′ of FIG. 1A.FIG. 1C illustrates a cross-sectional view taken along line B-B′ of FIG.1A. FIG. 1D illustrates a cross-sectional view taken along line C-C′ ofFIG. 1A.

Referring to FIGS. 1A, 1B, 1C, and 1D, a substrate 100 may be provided.The substrate 100 may be a semiconductor substrate. For example, thesubstrate 100 may be a silicon substrate, a germanium substrate, or asilicon-on-insulator (SOI) substrate.

The substrate 100 may be provided thereon with a plurality of memorycells to store data. For example, the substrate 100 may be providedthereon with memory cell transistors included in a plurality of SRAMcells.

A device isolation layer ST may be provided on the substrate 100. Thedevice isolation layer ST may define active structures AS1 to AS4, outerinactive patterns OIA1 to OIA4, and inner inactive patterns IIA1 to IIA4on an upper portion of the substrate 100.

The active structures AS1 to AS4, the outer inactive patterns OIA1 toOIA4, and the inner inactive patterns IIA1 to IIA4 may have their topportions that vertically protrude higher than the device isolation layerST. For example, each of the active structures AS1 to AS4, the outerinactive patterns OIA1 to OIA4, and the inner inactive patterns IIA1 toIIA4 may protrude to the same height in the third direction D3, and thatsame height may be higher than a height of the device isolation layer STin the third direction D3. Each of the upper portions of the activestructures AS1 to AS4, the outer inactive patterns OIA1 to OIA4, and theinner inactive patterns IIA1 to IIA4 may have a fin shape thatvertically protrudes from the device isolation layer ST. The deviceisolation layer ST may include a dielectric material (e.g., a siliconoxide layer).

The active structures AS1 to AS4 may include first to fourth activestructures AS1 to AS4. Each of the first to fourth active structures AS1to AS4 may include first to fourth active patterns AP1 to AP4. Each ofthe first to fourth active patterns AP1 to AP4 may have a linear or barshape extending lengthwise in a second direction D2 parallel to a topsurface of the substrate 100. An item, layer, or portion of an item orlayer described as extending “lengthwise” in a particular direction hasa length in the particular direction and a width perpendicular to thatdirection, where the length is greater than the width. The first tofourth active patterns AP1 to AP4 may be spaced apart from each other ina first direction D1 that is parallel to the top surface of thesubstrate 100 and intersects the second direction D2.

A first pitch P1 may be provided between the first and second activepatterns AP1 and AP2 of the second active structure AS2. A second pitchP2 may be provided between the second and third active patterns AP2 andAP3 of the second active structure AS2. A third pitch P3 may be providedbetween the third and fourth active patterns AP3 and AP4 of the secondactive structure AS2. A fourth pitch P4 may be provided between thefourth active pattern AP4 of the second active structure AS2 and thefirst active pattern AP1 of the third active structure AS3. In someembodiments, pitches of the first to fourth active patterns AP1 to AP4of the first, third, and fourth active structures AS1, AS3, and AS4 maybe the same as the corresponding pitches of the first to fourth activepatterns AP1 to AP4 of the second active structure AS2.

The first pitch P1 may be greater than the second pitch P2. The thirdpitch P3 may be greater than the second pitch P2. The fourth pitch P4may be greater than the second pitch P2.

The outer inactive patterns OIA1 to OIA4 may be disposed on oppositesides of the active structures AS1 to AS4, and the inner inactivepatterns IIA1 to IIA4 may also be disposed on the opposite sides of theactive structures AS1 to AS4. For example, pairs of each of the outerinactive patterns OIA1 to OIA4 and the inner inactive patterns IIA1 toIIA4 may be disposed on the opposite sides of the active structures AS1to AS4 such that they mirror one another. The outer inactive patternsOIA1 to OIA4 and the inner inactive patterns IIA1 to IIA4 may be curvedwhen viewed in plan. The outer inactive patterns OIA1 to OIA4 mayinclude first to fourth outer inactive patterns OIA1 to OIA4. The innerinactive patterns IIA1 to IIA4 may include first to fourth innerinactive patterns IIA1 to IIA4.

Pairs of the inner inactive patterns IIA1 to IIA4 may be spaced apart inthe second direction D2 from each other with the active patterns AP1 toAP4 therebetween. For example, a pair of the second inner inactivepatterns IIA2 may be spaced apart in the second direction D2 from eachother with the third and fourth active patterns AP3 and AP4 of thesecond active structure AS2 therebetween. As another example, a pair ofthe second inner inactive patterns IIA3 may be spaced apart in thesecond direction D2 from each other with the first and second activepatterns AP1 and AP2 of the third active structure AS3 therebetween.

A pair of the first outer inactive patterns OIA1 may be spaced apart inthe second direction D2 from each other with the first inner inactivepattern IIA1, the fourth active pattern AP4 of the first activestructure AS1, and the first active pattern AP1 of the second activestructure AS2. A pair of the second outer inactive patterns OIA2 may bespaced apart in the second direction D2 from each other with the secondinner inactive pattern IIA2 and the second to fourth active patterns AP2to AP4 of the second active structure AS2 therebetween. A pair of thethird outer inactive patterns OIA3 may be spaced apart in the seconddirection D2 from each other with the third inner inactive pattern IIA3and the first to third active patterns AP1 to AP3 of the third activestructure AS3 therebetween. A pair of the fourth outer inactive patternsOIA4 may be spaced apart in the second direction D2 from each otheracross the fourth inner inactive pattern IIA4, the fourth active patternAP4 of the third active structure AS4, and the first active pattern AP1of the fourth active structure AS4.

As discussed above, three of the active patterns AP1 to AP4 may bedisposed between a pair of the outer inactive patterns OIA1 to OIA4,where the pair faces each other in the second direction D2.

A first length L1 may be provided as a minimum length between a firstsegment of the second inner inactive pattern IIA2 and the second outerinactive pattern OIA2, which first segment is adjacent to the thirdactive pattern AP3 of the second active structure AS2. A second lengthL2 may be provided as a minimum length between a second segment of thesecond inner inactive pattern IIA2 and the second outer inactive patternOIA2, where the second segment is adjacent to the fourth active patternAP4 of the second active structure AS2. The first length L1 and thesecond length L2 may be substantially the same. In some embodiments, thelength (or distance) between an outer surface of a given inner inactivepattern IIA1 to IIA4 and an inner surface of a corresponding outerinactive pattern OIA1 to OIA4 may be uniform.

The first and second outer inactive patterns OIA1 and OIA2 may be spacedapart from each other in the first direction D1. The third and fourthouter inactive patterns OIA3 and OIA4 may be spaced apart from eachother in the first direction D1. The second and third outer inactivepatterns OIA2 and OIA3 may be connected to each other. For example, thesecond and third outer inactive patterns OIA2 and OIA3 may be combinedinto a single body (e.g., a monolithic structure).

The second outer inactive pattern OIA2 may have a third length L3corresponding to a maximum length of the second outer inactive patternOIA2 in the first direction D1 thereof. The third length L3 may begreater than a sum of the second pitch P2 and the third pitch P3. Thethird length L3 may be less than a sum of the second pitch P2, the thirdpitch P3, and the fourth pitch P4.

First source/drain patterns SD1 may be provided on each of the first andfourth active patterns AP1 and AP4. Second source/drain patterns SD2 maybe provided on each of the second and third active patterns AP2 and AP3.The first source/drain patterns SD1 may be n-type impurity regions. Thesecond source/drain patterns SD2 may be p-type impurity regions.

The first source/drain patterns SD1 may define a channel CH on an upperportion of each of the first and fourth active patterns AP1 and AP4, andthe second source/drain patterns SD2 may define a channel CH on an upperportion of each of the second and third active patterns AP2 and AP3.Each of the channels CH may be interposed between neighboring firstsource/drain patterns SD1 or between neighboring second source/drainpatterns SD2. For example, each of the channels CH may connectneighboring first source/drain patterns SD1 to each other or may connectneighboring second source/drain patterns SD2 to each other.

Each of the first source/drain patterns SD1 may be an epitaxial patternformed either from the channel CH and the first active pattern AP1 thatserve as a seed layer or from the channel CH and the fourth activepattern AP4 that serve as a seed layer. For example, the firstsource/drain patterns SD1 may be a semiconductor element whose latticeconstant is less than that of a semiconductor element of the substrate100. For another example, the first source/drain patterns SD1 may be thesame semiconductor element (e.g., silicon) as that of the substrate 100.

Each of the second source/drain patterns SD2 may be an epitaxial patternformed either from the channel CH and the second active pattern AP2 thatserve as a seed layer or from the channel CH and the third activepattern AP3 that serve as a seed layer. The second source/drain patternsSD2 may include a material that provides a compressive strain to thechannel CH therebetween. For example, the second source/drain patternsSD2 may be a semiconductor element (e.g., silicon-germanium) whoselattice constant is greater than that of a semiconductor element of thesubstrate 100.

The substrate 100 may be provided thereon with gate electrodes GErunning across the channels CH and extending lengthwise in the firstdirection D1. The gate electrodes GE may be spaced apart from each otherin the second direction D2. The gate electrodes GE may verticallyoverlap the channels CH. The gate electrodes GE may include, forexample, one or more of a conductive metal nitride (e.g., titaniumnitride or tantalum nitride) and a metal (e.g., titanium, tantalum,tungsten, copper, or aluminum).

A dielectric pattern IL may be provided on the substrate 100. Thedielectric pattern IL may be interposed between the gate electrodes GE.The dielectric pattern IL may separate the gate electrodes GE from eachother, electrically isolating each gate electrode GE.

A pair of gate spacers GS may be disposed on opposite sidewalls of eachof the gate electrodes GE. The gate spacers GS may extend lengthwise inthe first direction D1 along the gate electrodes GE. The gate spacers GSmay have their top surfaces higher than top surfaces of the gateelectrodes GE. The top surfaces of the gate spacers GS may be coplanarwith that of a first interlayer dielectric layer 110 which will bediscussed below. For example, the gate spacers GS may include one ormore of SiO₂, SiCN, SiCON, and SiN. For another example, the gatespacers GS may include a multi-layer that consists of two or more ofSiO₂, SiCN, SiCON, and SiN.

Gate dielectric patterns GI may be interposed between corresponding gateelectrodes GE and corresponding channels CH. The gate dielectricpatterns GI may also be interposed between the gate electrodes GE andthe gate spacers GS that extend along the gate electrodes GE. The gatedielectric patterns GI may include a high-k dielectric material. Forexample, the high-k dielectric material may include one or more ofhafnium oxide, hafnium silicon oxide, lanthanum oxide, zirconium oxide,zirconium silicon oxide, tantalum oxide, titanium oxide, bariumstrontium titanium oxide, barium titanium oxide, strontium titaniumoxide, lithium oxide, aluminum oxide, lead scandium tantalum oxide, andlead zinc niobate.

A gate capping pattern GP may be provided on each of the gate electrodesGE. The gate capping patterns GP may extend lengthwise in the firstdirection D1 along the gate electrodes GE. For example, the gate cappingpatterns GP may extend along top surfaces of the gate electrodes GE andbetween neighboring gate spacers GS. The gate capping patterns GP mayinclude a material having an etch selectivity with respect to first andsecond interlayer dielectric layers 110 and 120, which will be discussedbelow. For example, the gate capping patterns GP may include one or moreof SiON, SiCN, SiCON, and SiN.

A first interlayer dielectric layer 110 may be provided on an entiresurface of the substrate 100. The first interlayer dielectric layer 110may cover the device isolation layer ST, the gate electrodes GE, and thefirst and second source/drain patterns SD1 and SD2. The first interlayerdielectric layer 110 may have a top surface substantially coplanar withthose of the gate capping patterns GP. A second interlayer dielectriclayer 120 may be provided on the first interlayer dielectric layer 110.The first and second interlayer dielectric layers 110 and 120 mayinclude, for example, a silicon oxide layer or a silicon oxynitridelayer.

Active contacts AC may be provided to penetrate the first and secondinterlayer dielectric layers 110 and 120 and to have connection with thefirst and second source/drain patterns SD1 and SD2. The active contactsAC may have their top surfaces coplanar with that of the secondinterlayer dielectric layer 120. The active contacts AC may include ametallic material (e.g., titanium, tantalum, tungsten, copper, oraluminum).

Gate contacts GC may be provided on the gate electrodes GE. Each of thegate contacts GC may penetrate the second interlayer dielectric layer120 and the gate capping pattern GP and may have connection with thegate electrode GE. The gate contacts GC may have their top surfacescoplanar with that of the second interlayer dielectric layer 120. Thegate contacts GC may have their bottom surfaces higher than those of theactive contacts AC.

The gate contacts GC may include one or more of conductive metal nitride(e.g., titanium nitride or tantalum nitride) and metal (e.g., titanium,tantalum, tungsten, copper, or aluminum). The gate contacts GC mayinclude the same material as that of the active contacts AC. The gatecontact GC and its connected active contact AC may form a singleconductive structure.

FIGS. 2A, 3A, 4A, 5A, 6A, 7A, and 8A illustrate plan views showing amethod of fabricating a semiconductor device depicted in FIGS. 1A, 1B,1C, and 1D. FIGS. 2B, 3B, 4B, 5B, 6B, 7B, and 8B illustratecross-sectional views taken along line A-A′ of FIGS. 2A, 3A, 4A, 5A, 6A,7A, and 8A, respectively.

Referring to FIGS. 2A and 2B, a substrate 100 may be sequentiallyprovided thereon with a first mask layer 210, a second mask layer 220, athird mask layer 230, a fourth mask layer 250, a lower sacrificial layer260, a fifth mask layer 270, and an upper sacrificial layer (not shown).

Each of the first to fifth mask layers 210, 220, 230, 250, and 270, thelower sacrificial layer 260, and the upper sacrificial layer may includeone or more of silicon oxide (SiO₂), silicon oxynitride (SiON), siliconnitride (Si₃N₄), tetraethylorthosilicate (TEOS), polycrystallinesilicon, an amorphous carbon layer (ACL), and a spin-on-hardmask (SOH)layer. For example, the first mask layer 210 may include silicon oxide(SiO₂), the second mask layer 220 may include silicon nitride (Si₃N₄),the third mask layer 230 may include silicon oxide (SiO2), the fourthmask layer 250 may include polycrystalline silicon, the fifth mask layer270 may include polycrystalline silicon, the lower sacrificial layer 260may include an amorphous carbon layer (ACL), and the upper sacrificiallayer may include an amorphous carbon layer (ACL).

Each of the first to fifth mask layers 210, 220, 230, 250, and 270, thelower sacrificial layer 260, and the upper sacrificial layer may beformed by an atomic layer deposition (ALD) process, a chemical vapordeposition (CVD) process, or a spin coating process; a baking or curingprocess may be additionally performed depending their material.

The upper sacrificial layer may be patterned to form upper sacrificialpatterns 281 to 284. The upper sacrificial patterns 281 to 284 may beformed by a photolithography process. The upper sacrificial patterns 281to 284 may include first to fourth upper sacrificial patterns 281 to284. Four upper sacrificial patterns 281 to 284 are illustrated, but thenumber of the upper sacrificial patterns 281 to 284 may not be limitedto four.

The first to fourth upper sacrificial patterns 281 to 284 may bearranged along a first direction D1. For example, the first to fourthupper sacrificial patterns may be aligned along the first direction D1.The first to fourth upper sacrificial patterns 281 to 284 may be spacedapart from each other along the first direction D1. A fourth length L4may be provided as a minimum length in the first direction D1 betweenthe first and second upper sacrificial patterns 281 and 282. A fifthlength L5 may be provided as a minimum length in the first direction D1between the second and third upper sacrificial patterns 282 and 283. Asixth length L6 may be provided as a minimum length in the firstdirection D1 between the third and fourth upper sacrificial patterns 283and 284. The fourth length L4 and the sixth length L6 may besubstantially the same. The fifth length L5 may be less than each of thefourth length L4 and the sixth length L6.

Referring to FIGS. 3A and 3B, first to fourth upper spacers USP1 to USP4may be formed on sidewalls of the first to fourth upper sacrificialpatterns 281 to 284. The formation of the first to fourth upper spacersUSP1 to USP4 may include conformally forming an upper spacer layer on anentire surface of the substrate 100 and performing an etch-back process.The upper spacer layer may include a material having an etch selectivitywith respect to the first to fourth upper sacrificial patterns 281 to284. For example, the upper spacer layer may include silicon oxide orsilicon nitride. The upper spacer layer may be conformally formed by anatomic layer deposition (ALD) process.

The first upper spacer USP1 may be formed on the sidewall of the firstupper sacrificial pattern 281, the second upper spacer USP2 may beformed on the sidewall of the second upper sacrificial pattern 282, thethird upper spacer USP3 may be formed on the sidewall of the third uppersacrificial pattern 283, and the fourth upper spacer USP4 may be formedon the sidewall of the fourth upper sacrificial pattern 284.

The first and second upper spacers USP1 and USP2 may be spaced apartfrom each other in the first direction D1. The third and fourth upperspacers USP3 and USP4 may be spaced apart from each other in the firstdirection D1. The second and third upper spacers USP2 and USP3 may beconnected to each other between the second and third upper sacrificialpatterns 282 and 283. For example, the second and third upper spacersUSP2 and USP3 may be combined into a single body.

The first to fourth upper spacers USP1 to USP4 may have the same maximumwidth. Each of the first to fourth upper spacers USP1 to USP4 may have afirst width W1 corresponding to the maximum width thereof. The widths ofthe first to fourth upper spacers USP1 to USP4 may correspond to thedistance between inner and outer surfaces of the first to fourth upperspacers USP1 to USP4. Twice the first width W1 may be less than each ofthe fourth length L4 and the sixth length L6. Twice the first width W1may be greater than or substantially the same as the fifth length L5.For example, twice the first width W1 may be greater than orsubstantially the same as the minimum length in the first direction D1between the second upper sacrificial pattern 282 and the third uppersacrificial pattern 283.

Referring to FIGS. 4A and 4B, the first to fourth upper sacrificialpatterns 281 to 284 may be removed. Because the first to fourth uppersacrificial patterns 281 to 284 have an etch selectivity with respect tothe first to fourth upper spacers USP1 to USP4, the first to fourthupper sacrificial patterns 281 to 284 may be selectively removed under aspecific etching condition.

The first to fourth upper spacers USP1 to USP4 may be used as an etchingmask to pattern the fifth mask layer 270. The fifth mask layer 270 maybe patterned to form fifth mask patterns 271.

Referring to FIGS. 5A and 5B, the first to fourth upper spacers USP1 toUSP4 and the fifth mask patterns 271 may be used as an etching mask topattern the lower sacrificial layer 260. The lower sacrificial layer 260may be patterned to form first to fourth lower sacrificial patterns 261to 264.

The first to fourth lower sacrificial patterns 261 to 264 may verticallyoverlap the first to fourth upper spacers USP1 to USP4. For example, thefirst to fourth lower sacrificial patterns 261 to 264 may have a planarshape substantially the same as that of the first to fourth upperspacers USP1 to USP4.

Each of the first to fourth lower sacrificial patterns 261 to 264 mayinclude an inner sidewall ISW and an outer sidewall OSW.

Referring to FIGS. 6A and 6B, inner lower spacers ILSP may be formed onthe inner sidewalls ISW of the first to fourth lower sacrificialpatterns 261 to 264, and outer lower spacers OLSP may be formed on theouter sidewalls OSW of the first to fourth lower sacrificial patterns261 to 264. The formation of the inner and outer lower spacers ILSP andOLSP may include conformally forming a lower spacer layer on the entiresurface of the substrate 100 and performing an etch-back process. Thelower spacer layer may include a material having an etch selectivitywith respect to the first to fourth lower sacrificial patterns 261 to264. For example, the lower spacer layer may include silicon oxide orsilicon nitride. The lower spacer layer may be conformally formed by anatomic layer deposition (ALD) process.

The outer lower spacers OLSP may include first to fourth outer lowerspacers OLSP1 to OLSP4. The first outer lower spacer OLSP1 may be formedon the outer sidewall OSW of the first lower sacrificial pattern 261,the second outer lower spacer OLSP2 may be formed on the outer sidewallOSW of the second lower sacrificial pattern 262, the third outer lowerspacer OLSP3 may be formed on the outer sidewall OSW of the third lowersacrificial pattern 263, and the fourth outer lower spacer OLSP4 may beformed on the outer sidewall OSW of the fourth lower sacrificial pattern264.

The first and second outer lower spacers OLSP1 and OLSP2 may be spacedapart from each other in the first direction D1. The third and fourthouter lower spacers OLSP3 and OLSP4 may be spaced apart from each otherin the first direction D1. The second and third outer lower spacersOLSP2 and OLSP3 may be connected to each other. For example, the secondand third outer lower spacers OLSP2 and OLSP3 may be combined into asingle body (e.g., a monolithic structure).

Referring to FIGS. 7A and 7B, the first to fourth lower sacrificialpatterns 261 to 264 may be removed. Because the first to fourth lowersacrificial patterns 261 to 264 have an etch selectivity with respect tothe outer lower spacers OLSP and the inner lower spacers ILSP, the firstto fourth lower sacrificial patterns 261 to 264 may be selectivelyremoved under a specific etching condition.

The outer and inner lower spacers OLSP and ILSP may be used as anetching mask to pattern the fourth mask layer 250. The fourth mask layer250 may be patterned to form fourth mask patterns 251.

A side-cut process may be performed to pattern the outer lower spacersOLSP, the inner lower spacers ILSP, and the fourth mask patterns 251.The side-cut process may include performing a photolithography processto pattern the outer and inner lower spacers OLSP and ILSP and using thepatterned outer and inner lower spacers OLSP and ILSP as an etching maskto pattern the fourth mask patterns 251.

The side-cut process may form first segments SP1 and second segments SP2of each of the outer and inner lower spacers OLSP and ILSP. The secondsegments SP2 may be curved portions when viewed in plan. The firstsegments SP1 may be portions each having a linear or bar shape extendinglengthwise along a second direction D2. The first and second segmentsSP1 and SP2 may be spaced apart from each other in the second directionD2. A pair of the second segments SP2 may be disposed on opposite sidesof the first segment SP1.

The fourth mask patterns 251 patterned by the side-cut process mayvertically overlap the first and second segments SP1 and SP2 of each ofthe outer and inner lower spacers OLSP and ILSP. For example, the fourthmask patterns 251 patterned by the side-cut process may have theirplanar shapes substantially the same as those of the first and secondsegments SP1 and SP2 of each of the outer and inner lower spacers OLSPand ILSP.

Referring to FIGS. 8A and 8B, the fourth mask patterns 251 and the firstand second segments SP1 and SP2 of each of the outer and inner lowerspacers OLSP and ILSP may be used as an etching mask to pattern thefirst, second, and third mask layers 210, 220, and 230 and a portion ofthe substrate 100. The third mask layer 230 may be patterned to formthird mask patterns (not shown), the second mask layer 220 may bepatterned to form second mask patterns (not shown), and the first masklayer 210 may be patterned to form first mask patterns (not shown). Thesubstrate 100 may be partially patterned to form, on an upper portionthereof, active structures AS1 to AS4, outer inactive patterns OIA1 toOIA4, and inner inactive patterns IIA1 to IIA4.

According to some example embodiments of the present inventive concepts,a plurality of active patterns AP1 to AP4 may be formed by a quadruplepatterning technology (QPT) process in which the second and third uppersacrificial patterns 282 and 283 are used as mandrels. The QPT processmay include the formation of upper spacers and the formation of lowerspacers, as discussed above. For example, when the second uppersacrificial pattern 282 is formed on a first region RG1 of the substrate100, and when the third upper sacrificial pattern 283 is formed on asecond region RG2 of the substrate 100, two ones of the active patternsAP1 to AP4 may be eventually formed on each of the first and secondregions RG1 and RG2. No active pattern may be formed on a third regionRG3 between the first and second regions RG1 and RG2.

After the patterning process, a removal process may be performed onremaining outer and inner lower spacers OLSP and ILSP, the fourth maskpatterns 251, and the first to third mask patterns (not shown).

A device isolation layer ST may be formed to allow the active structuresAS1 to AS4, the outer inactive patterns OIA1 to OIA4, and the innerinactive patterns IIA1 to IIA4 to vertically protrude from the deviceisolation layer ST. The formation of the device isolation layer ST mayinclude forming a dielectric layer on the entire surface of thesubstrate 100, performing a planarization process to expose top surfacesof the second mask patterns, removing the first and second maskpatterns, and removing an upper portion of the dielectric layer so as tovertically protrude the active structures AS1 to AS4, the outer inactivepatterns OIA1 to OIA4, and the inner inactive patterns IIA1 to IIA4. Theplanarization process may include a chemical mechanical polishing (CMP)process. The dielectric layer may include a dielectric material (e.g., asilicon oxide layer).

Referring back to FIGS. 1A, 1B, 1C, and 1D, gate electrodes GE may beformed to run across the active structures AS1 to AS4 on the substrate100, and then gate capping patterns GP and gate spacers GS may beformed.

First source/drain patterns SD1 may be formed on the first and fourthactive patterns AP1 and AP4, and second source/drain patterns SD2 may beformed on the second and third active patterns AP2 and AP3.

A selective epitaxial growth process may be performed to form the firstand second source/drain patterns SD1 and SD2. The selective epitaxialgrowth process may include, for example, a chemical vapor deposition(CVD) process or a molecular beam epitaxy (MBE) process. Simultaneouslyduring or after the selective epitaxial growth process, the firstsource/drain patterns SD1 may be doped with n-type impurities, and thesecond source/drain patterns SD2 may be doped with p-type impurities.

A first interlayer dielectric layer 110 and a second interlayerdielectric layer 120 may be formed on the entire surface of thesubstrate 100.

Active contacts AC may be formed to penetrate the first and secondinterlayer dielectric layers 110 and 120 and to have connection with thefirst and second source/drain patterns SD1 and SD2. Gate contacts GC maybe formed to penetrate the second interlayer dielectric layer 120 andthe gate capping patterns GP and to have connection with the gateelectrodes GE. The formation of the active contacts AC and the gatecontacts GC may include forming holes to define areas where the activecontacts AC and the gate contacts GC are formed and forming a conductivelayer to fill the holes.

In a method of fabricating a semiconductor device according to thepresent inventive concepts, a removal process of active patterns may beomitted to reduce fabrication cost and time.

FIG. 9A illustrates a plan view showing a semiconductor device accordingto some example embodiments of the present inventive concepts. FIG. 9Billustrates a cross-sectional view taken along line A-A′ of FIG. 9A.FIG. 9C illustrates a cross-sectional view taken along line B-B′ of FIG.9A.

For brevity of description, the same components as those discussed withreference to FIGS. 1A, 1B, 1C, and 1D are allocated the same referencenumerals thereto, and a duplicate explanation will be omitted.

Referring to FIGS. 9A, 9B, and 9C, a device isolation layer ST may beprovided on a substrate 100. The device isolation layer ST may defineactive structures AS1 to AS3, outer inactive patterns OIA1 to OIA5, andinner inactive patterns IIA1 to IIA5 on an upper portion of thesubstrate 100.

The active structures AS1 to AS3 may include first to third activestructures AS1 to AS3. Each of the first to third active structures AS1to AS3 may include first to third active patterns AP1 to AP3.

A first pitch P1 may be provided between the first and second activepatterns AP1 and AP2 of the first active structure AS1. A second pitchP2 may be provided between the second and third active patterns AP2 andAP3 of the first active structure AS1. The first and second pitches P1and P2 may be substantially the same.

The outer inactive patterns OIA1 to OIA5 may be disposed on oppositesides of the active structures AS1 to AS3, and the inner inactivepatterns IIA1 to IIA5 may also be disposed on the opposite sides of theactive structures AS1 to AS3. The outer inactive patterns OIA1 to OIA5may include first to fifth outer inactive patterns OIA1 to OIA5. Theinner inactive patterns IIA1 to IIA5 may include first to fifth innerinactive patterns IIA1 to IIA5.

A pair of the inner inactive patterns IIA1 to IIA5 may be spaced apartin a second direction D2 from each other with the active patterns AP1 toAP3 therebetween. For example, a pair of the second inner inactivepatterns IIA2 may be spaced apart in the second direction D2 from eachother with the second and third active patterns AP2 and AP3 of the firstactive structure AS1 therebetween.

A pair of the outer inactive patterns OIA1 to OIA5 may be spaced apartin the second direction D2 from each other with the active patterns AP1to AP3 and the inner inactive patterns IIA1 to IIA5 therebetween. Forexample, a pair of the second outer inactive patterns OIA2 may be spacedapart in the second direction D2 from each other with the second innerinactive patterns IIA2 and the second and third active patterns AP2 andAP3 of the first active structure AS1 therebetween.

As discussed above, two of the active patterns AP1 to AP3 may bedisposed between a pair of the outer inactive patterns OIA1 to OIA5,where the individual ones of each pair are opposite one other in thesecond direction D2.

The first to fifth outer inactive patterns OIA1 to OIA5 may be connectedto each other. For example, the first to fifth outer inactive patternsOIA1 to OIA5 may be combined into a single body (e.g., a monolithicstructure).

The second outer inactive pattern OIA2 may have a first length L1corresponding to a maximum length in a first direction D1 thereof. Thefirst length L1 may be substantially the same as a sum of the first andsecond pitches P1 and P2.

First source/drain patterns SD1 may be provided on each of the firstactive patterns AP1. Second source/drain patterns SD2 may be provided oneach of the second and third active patterns AP2 and AP3. The firstsource/drain patterns SD1 may be n-type impurity regions. The secondsource/drain patterns SD2 may be p-type impurity regions.

The first source/drain patterns SD1 may define a channel CH on an upperportion of each of the first active patterns AP1, and the secondsource/drain patterns SD2 may define a channel CH on an upper portion ofeach of the second and third active patterns AP2 and AP3.

FIGS. 10A, 11A, 12A, 13A, 14A, 15A, and 16A illustrate plan viewsshowing a method of fabricating a semiconductor device depicted in FIGS.9A, 9B, and 9C. FIGS. 10B, 11B, 12B, 13B, 14B, 15B, and 16B illustratecross-sectional views taken along line A-A′ of FIGS. 10A, 11A, 12A, 13A,14A, 15A, and 16A, respectively.

For brevity of description, the same components as those discussed withreference to FIGS. 2A, 2B, 3A, 3B, 4A, 4B, 5A, 5B, 6A, 6B, 7A, 7B, 8A,and 8B are allocated the same reference numerals thereto, and arepetitive explanation will be omitted.

Referring to FIGS. 10A and 10B, a substrate 100 may be sequentiallyprovided thereon with a first mask layer 210, a second mask layer 220, athird mask layer 230, a fourth mask layer 250, a lower sacrificial layer260, a fifth mask layer 270, and an upper sacrificial layer (not shown).

The upper sacrificial layer may be patterned to form upper sacrificialpatterns 281 to 285. The upper sacrificial patterns 281 to 285 mayinclude first to fifth upper sacrificial patterns 281 to 285. Five uppersacrificial patterns 281 to 285 are illustrated, but the number of theupper sacrificial patterns 281 to 285 may not be limited to five.

The first to fifth upper sacrificial patterns 281 to 285 may be arrangedalong a first direction D1. The first to fifth upper sacrificialpatterns 281 to 285 may be spaced apart from each other along the firstdirection D1. A second length L2 may be provided as a minimum length inthe first direction D1 between the first and second upper sacrificialpatterns 281 and 282. A third length L3 may be provided as a minimumlength in the first direction D1 between the second and third uppersacrificial patterns 282 and 283. A fourth length L4 may be provided asa minimum length in the first direction D1 between the third and fourthupper sacrificial patterns 283 and 284. The second to fourth lengths L2to L4 may be substantially the same.

Referring to FIGS. 11A and 11B, first to fifth upper spacers USP1 toUSP5 may be formed on sidewalls of the first to fifth upper sacrificialpatterns 281 to 285.

The first to fifth upper spacers USP1 to USP5 may be connected to eachother. For example, the first to fifth upper spacers USP1 to USP5 may becombined into a single body (e.g., a monolithic structure).

Each of the first to fifth upper spacers USP1 to USP5 may have a firstwidth W1 corresponding to a maximum width thereof. The widths of thefirst to fifth upper spacers USP1 to USP5 may correspond to the distancebetween inner and outer surfaces of the first to fifth upper spacersUSP1 to USP5. Twice the first width W1 may be greater than orsubstantially the same as each of the second to fourth lengths L2 to L4.For example, twice the first width W1 may be greater than orsubstantially the same as the minimum length in the first direction D1between the first and second upper sacrificial patterns 281 and 282, theminimum length in the first direction D1 between the second and thirdupper sacrificial patterns 282 and 283, or the minimum length in thefirst direction D1 between the third and fourth upper sacrificialpatterns 283 and 284.

Referring to FIGS. 12A and 12B, the first to fifth upper sacrificialpatterns 281 to 285 may be removed.

The first to fifth upper spacers USP1 to USP5 may be used as an etchingmask to pattern the fifth mask layer 270. The fifth mask layer 270 maybe patterned to form fifth mask patterns 271.

Referring to FIGS. 13A and 13B, the first to fifth upper spacers USP1 toUSP5 and the fifth mask patterns 271 may be used as an etching mask topattern the lower sacrificial layer 260. The lower sacrificial layer 260may be patterned to form first to fifth lower sacrificial patterns 261to 265.

The first to fifth lower sacrificial patterns 261 to 265 may verticallyoverlap the first to fifth upper spacers USP1 to USP5. For example, thefirst to fifth lower sacrificial patterns 261 to 265 may have a planarshape substantially the same as that of the first to fifth upper spacersUSP1 to USP5.

Each of the first to fifth lower sacrificial patterns 261 to 265 mayinclude an inner sidewall ISW and an outer sidewall OSW.

Referring to FIGS. 14A and 14B, inner lower spacers ILSP may be formedon the inner sidewalls ISW of the first to fifth lower sacrificialpatterns 261 to 265, and outer lower spacers OLSP may be formed on theouter sidewalls OSW of the first to fifth lower sacrificial patterns 261to 265.

The outer lower spacers OLSP may be connected to each other. Forexample, the outer lower spacers OLSP may be combined into a single body(e.g., a monolithic structure).

Referring to FIGS. 15A and 15B, the first to fifth lower sacrificialpatterns 261 to 265 may be removed.

The outer and inner lower spacers OLSP and ILSP may be used as anetching mask to pattern the fourth mask layer 250. The fourth mask layer250 may be patterned to form fourth mask patterns 251.

A side-cut process may be performed to pattern the inner lower spacersILSP and the fourth mask patterns 251. The side-cut process may notpattern the outer lower spacers OLSP. For example, the side-cut processmay have no effect on the outer lower spacers OLSP.

The side-cut process may form first segments SP1 and second segments SP2of the inner lower spacers ILSP.

The fourth mask patterns 251 patterned by the side-cut process mayvertically overlap the first and second segments SP1 and SP2 of theinner lower spacers ILSP.

Referring to FIGS. 16A and 16B, the outer lower spacers OLSP, the firstand second segments SP1 and SP2 of the inner lower spacers ILSP, and thefourth mask patterns 251 may be used as an etching mask to pattern thefirst, second, and third mask layers 210, 220, and 230 and a portion ofthe substrate 100. The third mask layer 230 may be patterned to formthird mask patterns (not shown), the second mask layer 220 may bepatterned to form second mask patterns (not shown), and the first masklayer 210 may be patterned to form first mask patterns (not shown). Thesubstrate 100 may be partially patterned to form, on an upper portionthereof, active structures AS1 to AS3, outer inactive patterns OIA1 toOIA5, and inner inactive patterns IIA1 to IIA5.

According to some example embodiments of the present inventive concepts,a plurality of active patterns AP1 to AP3 may be formed by a quadruplepatterning technology (QPT) process in which the second and third uppersacrificial patterns 282 and 283 are used as mandrels. The QPT processmay include the formation of upper spacers and the formation of lowerspacers, as discussed above. For example, when the second uppersacrificial pattern 282 is formed on a first region RG1 of the substrate100, and when the third upper sacrificial pattern 283 is formed on asecond region RG2 of the substrate 100, two ones of the active patternsAP1 to AP3 may be eventually formed on each of the first and secondregions RG1 and RG2. No active pattern may be formed on a third regionRG3 between the first and second regions RG1 and RG2. After thepatterning process, a removal process may be performed on remainingouter and inner lower spacers OLSP and ILSP, the fourth mask patterns251, and the first to third mask patterns.

A device isolation layer ST may be formed to allow the active structuresAS1 to AS3, the outer inactive patterns OIA1 to OIA5, and the innerinactive patterns IIA1 to IIA5 to vertically protrude from the deviceisolation layer ST.

Referring back to FIGS. 9A, 9B, and 9C, gate electrodes GE may be formedto run across the active structures AS1 to AS3 on the substrate 100, andthen gate capping patterns GP and gate spacers GS may be formed.

First source/drain patterns SD1 may be formed on the first activepatterns AP1, and second source/drain patterns SD2 may be formed on thesecond and third active patterns AP2 and AP3.

A first interlayer dielectric layer 110 and a second interlayerdielectric layer 120 may be formed on an entire surface of the substrate100. Active contacts AC may be formed to penetrate the first and secondinterlayer dielectric layers 110 and 120 and to have connection with thefirst and second source/drain patterns SD1 and SD2. Gate contacts GC maybe formed to penetrate the second interlayer dielectric layer 120 andthe gate capping patterns GP and to have connection with the gateelectrodes GE.

In a method of fabricating a semiconductor device according to thepresent inventive concepts, a removal process of active patterns may beomitted to reduce fabrication cost and time.

Although exemplary embodiments of the present inventive concepts havebeen discussed with reference to accompanying figures, it will beunderstood that various changes in form and details may be made thereinwithout departing from the spirit and scope of the present inventiveconcepts. It therefore will be understood that the some exampleembodiments described above are just illustrative but not limitative inall aspects.

What is claimed is:
 1. A method of fabricating a semiconductor device, the method comprising: sequentially stacking a lower sacrificial layer and an upper sacrificial layer on a substrate; patterning the upper sacrificial layer to form a first upper sacrificial pattern and a second upper sacrificial pattern; forming a first upper spacer and a second upper spacer on sidewalls of the first upper sacrificial pattern and the second upper sacrificial pattern, respectively; patterning the lower sacrificial layer, using the first and second upper spacers as an etching mask, to form a plurality of lower sacrificial patterns; forming a plurality of lower spacers on sidewalls of the lower sacrificial patterns; and patterning the substrate using the plurality of lower spacers as an etching mask, wherein the first and second upper spacers are connected to each other.
 2. The method of claim 1, wherein twice a maximum width of each of the first and second upper spacers is greater than a minimum length between the first and second upper sacrificial patterns.
 3. The method of claim 2, wherein patterning the upper sacrificial layer comprises forming a third upper sacrificial pattern, wherein twice the maximum width of each of the first and second upper spacers is less than a minimum length between the second and third upper sacrificial patterns.
 4. The method of claim 1, wherein the first and second upper spacers are connected to each other between the first and second upper sacrificial patterns.
 5. The method of claim 1, further comprising: performing a side-cut process to pattern the lower spacers to form a plurality of first segments and a plurality of second segments.
 6. The method of claim 5, wherein the first segments have a bar shape, and wherein the second segments are curved when viewed in plan.
 7. The method of claim 6, wherein two of the second segments are connected each other.
 8. The method of claim 1, wherein patterning the substrate comprises: forming first to sixth active patterns sequentially provided along a first direction on an upper portion of the substrate; forming a pair of first inner inactive patterns spaced apart from each other with the second and third active patterns therebetween; forming a pair of second inner inactive patterns spaced apart from each other with the fourth and fifth active patterns therebetween; forming a pair of first outer inactive patterns spaced apart from each other with the first to third active patterns and the pair of first inner inactive patterns therebetween; and forming a pair of second outer inactive patterns spaced apart from each other with the fourth to sixth active patterns and the pair of second inner inactive patterns therebetween.
 9. The method of claim 8, wherein the pair of first outer inactive patterns are connected to the pair of second outer inactive patterns.
 10. The method of claim 9, wherein a maximum length in the first direction of a first outer inactive pattern of the pair of first outer inactive patterns is greater than a sum of a first pitch between the first and second active patterns and a second pitch between the second and third active patterns.
 11. The method of claim 10, wherein the maximum length in the first direction of the first outer inactive pattern is less than a sum of the first pitch, the second pitch, and a third pitch between the third and fourth active patterns.
 12. A method of fabricating a semiconductor device, the method comprising: forming a first upper sacrificial pattern and a second upper sacrificial pattern respectively on a first region and a second region of a substrate; and performing a quadruple patterning technology (QPT) process in which the first and second upper sacrificial patterns are used as mandrels to form a plurality of active patterns on an upper portion of the substrate, wherein the active patterns are not formed on a third region between the first region and the second region.
 13. The method of claim 12, wherein performing the QPT process comprises: forming a plurality of upper spacers on sidewalls of the first and second upper sacrificial patterns; forming a plurality of lower sacrificial patterns using the plurality of upper spacers as an etching mask; and forming a plurality of lower spacers on sidewalls of the plurality of lower sacrificial patterns, wherein twice a maximum width of each of the upper spacers is greater than a minimum length between the first and second upper sacrificial patterns.
 14. The method of claim 13, wherein forming the lower spacers comprises: forming a plurality of inner lower spacers on inner sidewalls of the lower sacrificial patterns; and forming a plurality of outer lower spacers on outer sidewalls of the lower sacrificial patterns, wherein the outer lower spacers are connected to each other.
 15. The method of claim 14, further comprising: performing a side-cut process to pattern the inner lower spacers to form a plurality of first segments and a plurality of second segments.
 16. A semiconductor device, comprising: a substrate; first to third active patterns sequentially provided along a first direction on an upper portion of the substrate, wherein the first to third active patterns extend lengthwise in parallel along a second direction; a pair of first inner inactive patterns spaced apart in the second direction from each other with the second and third active patterns therebetween; and a pair of first outer inactive patterns spaced apart in the second direction from each other with the first to third active patterns and the pair of first inner inactive patterns therebetween.
 17. The semiconductor device of claim 16, wherein each first inner active pattern of the pair of first inner inactive patterns comprises a first segment adjacent to the second active pattern and a second segment adjacent to the third active pattern, wherein a minimum length between the first segment and a first outer inactive pattern of the pair of first outer inactive patterns is substantially the same as a minimum length between the second segment and the first outer inactive pattern.
 18. The semiconductor device of claim 16, wherein a maximum length in the first direction of a first outer inactive pattern of the pair of first outer inactive patterns is greater than a sum of a first pitch between the first and second active patterns and a second pitch between the second and third active patterns.
 19. The semiconductor device of claim 18, further comprising: fourth to sixth active patterns sequentially provided along the first direction on the upper portion of the substrate; a pair of second inner inactive patterns spaced apart in the second direction from each other with the fourth and fifth active patterns therebetween; and a pair of second outer inactive patterns spaced apart in the second direction from each other with the fourth to sixth active patterns and the pair of second inner inactive patterns therebetween, wherein the pairs of first and second outer inactive patterns are connected to each other.
 20. The semiconductor device of claim 19, wherein the maximum length in the first direction of the first outer inactive pattern is less than a sum of the first pitch, the second pitch, and a third pitch between the third and fourth active patterns. 